Small Craft Advisory 1097, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
415 AM AST FRI DEC 28 2007

.MODEL DISCUSSION...
MODELS PERFORMING REASONABLY WELL. PREFERRED GFS OVERALL...BUT NAM
HANDLING SOME FEATURES NEAR TERRAIN BETTER IN THE SHORT TERM.

.ANALYSIS AND UPPER LEVELS...
UPPER TROUGH OVER THE BERING SEA WITH A NEGATIVE TILTED TROUGH
STRETCHING FROM BRITISH COLUMBIA THROUGH THE YUKON AND BARROW AND
INTO THE ARCTIC OCEAN. MAIN JET STREAM IS WELL SOUTH OF THE AREA
RUNNING ALONG ABOUT 40 DEGREES NORTH LATITUDE...ARCING OVER A STRONG
SUB-TROPICAL RIDGE SOUTH OF ALASKA. THE ARCTIC JET IS APPROXIMATELY
OVER THE ALEUTIANS AND INTO SOUTHWEST ALASKA...THEN SPLITS AS IT
HITS THE BLOCKING HIGH MENTIONED ABOVE.

SEVERAL SYSTEMS IN THE ARCTIC JET AR CURRENTLY AFFECTING ALASKA. ONE
IS JUST EAST OF KODIAK AND STALLING...ONE IS NORTHWEST OF THE
PRIBILOFS...AND ONE SOUTH OF COLD BAY.

.SHORT TERM FORECAST...
THE KODIAK LOW WILL CONTINUE TO SHEAR OUT TODAY AS IT PRESSES INTO
THE RIDGE. SNOW FROM THIS SYSTEM WILL MOVE NORTHEAST TO ABOUT
ANCHORAGE TODAY...THEN FIZZLE OUT TONIGHT. THE COLD BAY SYSTEM WILL
BRING SNOW TO THE PENINSULA TODAY...THEN RACE OFF TO THE EAST AS IT
IS SOMEWHAT INVOLVED WITH THE MAIN JET STREAM. THE PRIBILOF LOW WILL
SLOWLY DRIFT NORTH...WITH SHOWERS LIBERALLY SPREAD ACROSS THE BERING
SEA AND ALEUTIANS TODAY AND TONIGHT. ANOTHER SYSTEM WILL CROSS JUST
SOUTH OF THE ALEUTIANS THROUGH SUNDAY.

.LONG TERM FORECAST...
THE LAST SYSTEM MENTIONED ABOVE WILL BE THE PRECURSOR TO A PATTERN
CHANGE. BY LATE IN THE WEEKEND THIS SYSTEM WILL SPIN UP...PULLING
COLD AIR FROM SIBERIA AND TAPPING THE JET STREAM TO THE SOUTH. THIS
WILL INITIATE A SURFACE LOW BOMBING OUT IN THE CENTRAL GULF BY
SUNDAY NIGHT...THEN MOVING INTO THE NORTHERN GULF BY TUESDAY AND
BECOMING A MAJOR STEERING LOW. THE BLOCKING RIDGE WILL STRENGTHEN
AND BECOME A FULL LATITUDE FEATURE ALONG THE WEST COAST OF NORTH
AMERICA AND ACROSS EASTERN ALASKA. A WEAKER RIDGE WILL FORM BEHIND
THIS LOW OVER THE BERING SEA. THIS WILL FINISH THE PROGRESSION FROM
THE CURRENT ZONAL FLOW TO A MUCH HIGHER AMPLITUDE FLOW OVER THE
EASTERN PACIFIC AND NORTH AMERICA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING 130 132 138 150 155 170 172 179 185.
         HEAVY FREEZING SPRAY 130 138 140 160 180 179 185.
FIRE WEATHER...NONE.

LUDWIG DEC 07